The present invention relates generally to apparatus useful in coating the surface of an item. More particularly, the present invention concerns apparatus for applying desired amounts of lubricant to each side of a continuous sheet of material used in the formation of a manufactured product. Specifically, the present invention relates to an improved coating station for coating the surface of a continuous sheet of aluminum used during the formation of aluminum cans.
In the manufacture of aluminum cans, it is customary to feed a continuous strip or sheet of aluminum to a punch press that forms shallow cup-shaped blanks from the strip of material. The shallow cup-shaped blanks are then used in a body maker machine which pushes the blanks through can forming and ironing dies to elongate and shape the shallow cup-shaped blanks into aluminum can bodies. These operations require substantial contact between the various die apparatus and the aluminum sheet material. As a result of this contact and to reduce friction, it is necessary to apply a lubricating material to each side of the continuous sheet of aluminum prior to feeding the sheet material into the punch press and dies.
One conventional method of applying such lubricant layer to a continuous strip of aluminum is to pull the continuous strip of aluminum through a bath of lubricating material and then squeeze off any excess lubricant. As an alternative to this bath technique, a device and method for applying lubricant to a continuous sheet of aluminum material is disclosed in U.S. Pat. No. 5,549,752, the contents of which are specifically incorporated herein by reference. In this particular patent, a device is disclosed wherein coating stations are located on each side of a continuous sheet of material, and lubricant is dispersed onto the sides of the material in regulated amounts. Unfortunately, a complicated plunger mechanism in combination with the lubricant supply is required, and highly accurate control and adjustment of the amount of lubricant applied to the sheet of material remains elusive.
Consequently, there remains a need for an apparatus and technique wherein thin layers of lubricant may be applied to one or both sides of a continuous sheet of material in accurate amounts and wherein such amounts may be readily adjusted.
It is an object of the present invention to provide a new and useful coating device and a coating apparatus incorporating such device so as to apply a coating material to at least one side of a strip of material.
It is another object of the present invention to provide a new and useful coating station comprising a pair of coating devices so as to coat both sides of a strip of material.
Another object of the present invention is to provide an improved coating apparatus for deposing a layer of lubricant onto the surface of a continuous sheet of material wherein the amount of lubricant may be adjustable.
A further object of the present invention is to provide an apparatus for distributing careful metered amounts of lubricant onto a moving sheet of material or surface of an item.
Still a further object of the present invention is to provide a rotary metering assembly for supplying a coating material to a wick that is in contact with a sheet of material or surface of an item in order to apply the coating the material thereon.
According to the present invention, then, a coating device is provided that is operative to apply a coating of material from a source to the surface of an item. Broadly, the coating device of the present invention includes a housing that has a conduit adapted to connect to a source of coating material. A wick is supported by the housing and is adapted to contact the surface of the item. The housing has a fluid dispensing passageway in the form of intake port and fluid communication with the conduit and a discharge port in fluid communication with the wick. A metering member is interposed in the fluid dispensing passageway and is rotatably journaled in the housing about a longitudinal axis of rotation. The metering member has a metering bore formed therein, and a metering piston is disposed in the metering bore for reciprocation therein. A meter drive operates to rotate the metering member about the longitudinal axis. As the drive rotates the metering member, the metering bore is moved between the intake port wherein it receives coating material and a discharge port wherein the material is dispensed by the piston to the wick.
Preferably, the housing has a cylindrical chamber and the metering member is formed as a cylindrical shaft disposed in the chamber. The metering bore is then formed radially in the shaft, and preferably diametrically completely through the shaft. Here, also, the intake port and the discharge port are oriented in opposed, coaxial relationship to one another with the shaft being interposed between the intake port and the discharge port such that the metering bore rotates into and out of coaxial alignment with the intake port and the discharge port as the shaft is rotated.
Preferably, the housing has a plurality of longitudinally spaced fluid dispensing passageways each having an intake port and a discharge port that define a pair of dispensing ports. The metering member is then provided with a plurality of longitudinally spaced metering bores in one-to-one correspondence to the fluid dispensing passageways, and each of the metering bores is provided with a metering piston disposed therein. Adjacent ones of the fluid dispensing passageways are equidistantly spaced from one another. The conduit is formed, then, as a manifold supply having a plurality of outlets corresponding to each of the dispensing passageways.
The coating apparatus of the present invention includes at least one coating device as described above. A frame supports each of the coating devices. A meter drive is operative to rotate the metering member of each coating device about its longitudinal axis, and a strip drive is operative to advance the strips of material past the coating device. Preferably, two coating devices are provided in opposed relationship to one another thereby defining a coating station through which the strip of material is advanced. In such manner, both surfaces of the strips of material are simultaneously coated with the coating material.
It should thus be appreciated that the apparatus according to the present invention provides a plurality of metering elements disposed between the intake ports and the discharge ports to distribute a predetermined amount of coating material onto the wick. As noted above, these metering elements are preferably piston members disposed in longitudinally spaced transverse bores in a cylindrically rotating shaft. The volume of fluid or coating material dispensed in the coating device of the present invention may be varied either by changing the size of the bores in the metering shaft, by changing the size of the pistons, or changing the speed of rotation of the dispensing shaft.
These and other objects of the present invention will become more readily appreciated and understood from a consideration of the following detailed description of the exemplary embodiment of the present invention when taken together with the accompanying drawings, in which: